Police investigating the knife murder of a teenager as he tried to retrieve his younger brother’s stolen BlackBerry have released a CCTV image of a suspect.

A huge manhunt is under way for Dawda Jallow, 15, who police believe is being sheltered by friends or family in London. The picture shows Jallow on a No 35 bus about five hours after the murder.

He boarded at Camberwell Green and alighted at Newington Causeway at 10.32pm on Sunday

Business student Dogan Ismail, 17, died after being stabbed once in the chest on Walworth’s notorious Aylesbury Estate yards from where father-to-be Shaun Chambers, 21, was murdered in September.

Dogan died after collapsing in the arms of his brother Orhan, 15, just before 4.20pm. Dogan, who had no links to gangs or crime, is believed to have gone to the estate to protect his brother after muggers vowed to return Orhan’s phone at a face-to-face meeting.

Today it emerged that Orhan has received a sick message blaming him for the killing of his brother.

Gambian national Jallow is described as 5ft 5in tall and of slight build. Det Ch Insp Matt Bonner, who is leading the murder hunt, said: “We are taking the rare step of publicising Jallow’s name and image as it is critical he is found as soon as possible. I appeal to people, particularly anyone helping him, to look to their conscience and inform us of his whereabouts.”